Book/Report

FZJ-2018-00638

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Anelastische Relaxationsprozesse in Aluminium nach Elektronenbestrahlung bei tiefen Temperaturen

Spiric, V. (Corresponding author)FZJ*

1976
Kernforschungsanlage Jülich, Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/16629

Report No.: Juel-1270

Abstract: Anelastic relaxation processes in single crystals of aluminum have been investigated after 3 MeV-electron irradiation at 4.5 K. The elastic after-effect measurements were made on torsionally stressed <111> and <100> samples (defect concentration 7$\cdot$10$^{-4}$ and 4$\cdot$10$^{-4}$ respectively). The elastic after-effect method is weIl suited for investigating such relaxation processes where a defect reorientation jump mayaIso lead to migration, and therefore through reactions with other defects in the lattice, to annihilation of the relaxing defect. The advantage of the elastic after-effect method is that it requires only a few defect reorientation jumps in comparison to the several thousand necessary for an internal friction measurement. In addition to the relaxation processes which have been seen previously in internal friction studies, two new processes, A and B, have been observed. Process A has been identified as the reorientational relaxation of <100>-dumbbell interstitials in recovery stage I$_{D+E}$. The measured activation energy (115 meV) for process A shows that reorientation and migration of thisdefect occurs by the same jump process. The value found for the elastic shape factor ($\vert$A-B$\vert$ = 1.1 eV) is consistent with that expected from theoretical estimateso Process B exhibits all the characteristics expected for reorientation of the Johnson di-interstitial in stage II$_{1}$. The defect symmetry and activationenergy for other relaxation processes have been determined, and possible configurations for corresponding defects are discussed. The dose dependence and annealing behaviour of the diaelastic modulus change have also been measured. The anisotropy and magnitude of the diaelastic effect indicate that the interstitialdefect created during irradiation at liquid helium temperature assumes the <100>-split configuration. The annealing behaviour indicates that interstitial atoms in small clusters have an even higher diaelastic polarizability than single interstitials, and that the diaelastic polarizability decreases strongly when the interstitials form dislocation loops.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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